Chromatin organization, facilitated by compartmentalization and loop extrusion, is crucial for proper gene expression and cell viability. Transcription has long been considered important for shaping genome architecture due to its pervasive activity across the genome and impact on the local chromatin environment. Although earlier studies suggested a minimal contribution of transcription to shaping global genome structure, recent insights from high-resolution chromatin contact mapping, polymer simulations, and acute perturbations have revealed its critical role in dynamic chromatin organization at the level of active genes and enhancer-promoter interactions. In this review, we discuss these latest advances, highlighting the direct interplay between transcriptional machinery and loop extrusion. Finally, we explore how transcription of genes and non-coding regulatory elements may contribute to the specificity of gene regulation, focusing on enhancers as sites of targeted cohesin loading.
The integration of artificial intelligence, machine learning and quantum computing into molecular dynamics simulations is catalyzing a revolution in computational biology, improving the accuracy and efficiency of simulations. This review describes the advancements and applications of these technologies to process vast molecular dynamics simulation datasets, adapt parameters of simulations and gain insight into complex biological processes. These advances include the use of predictive force fields, adaptive algorithms and quantum-assisted methodologies. While the integration of artificial intelligence and quantum computing with MD simulations provides insightful and stimulating improvements to our understanding of molecular mechanisms, it could introduce new issues related to data quality, interpretability of models and computational complexity. Modern multidisciplinary approaches are needed to navigate these challenges and exploit the potential of these emerging technologies for MD simulations of biomolecular systems.
Chromatin is a complex of DNA with histone proteins organized into nucleosomes that regulates genome accessibility and controls transcription, replication and repair by dynamically switching between open and compact states as a function of different parameters including histone post-translational modifications and interactions with chromatin modulators. Continuing advances in structural biology techniques including X-ray crystallography, cryo-electron microscopy and nuclear magnetic resonance (NMR) spectroscopy have facilitated studies of chromatin systems, in spite of challenges posed by their large size and dynamic nature, yielding important functional and mechanistic insights. In this review we highlight recent applications of magic angle spinning solid-state NMR – an emerging technique that is uniquely-suited toward providing atomistic information for rigid and flexible regions within biomacromolecular assemblies – to detailed characterization of structure, conformational dynamics and interactions for histone core and tail domains in condensed nucleosomes and oligonucleosome arrays mimicking chromatin at high densities characteristic of the cellular environment.